It is feasible to realize a fast particle source to emit particles such as electrons, protons, or deuterons at high speed from a target, by focusing a high-intensity laser on the target in vacuum (for example, reference is made to Document 1 “A. Maksimchuk, S. Gu, K. Flippo, and D. Umstadter, “Forward Ion Acceleration in Thin Films Driven by a High-Intensity Laser,” Phys. Rev. Lett. Vol. 84, pp. 4108-4111 (2000)” and Document 2 “I. Spencer et al., “Laser generation of proton beams for the production of short-lived positron emitting radioisotopes,” Nucl. Inst. and Meth. in Phys. Res. B Vol. 183, pp. 449-458 (2001)”). Such fast particle sources are applicable to various devices for generation of isotopes and others.
An example of such application is a generating apparatus of radioisotopes used in diagnoses with PET (Positron Emission Tomography) apparatus. The PET diagnoses use agents containing short-lived radioisotopes such as 11C, 13N, and 15O which emit positrons. These radioisotopes can be generated, for example, by making use of the (p,n) reaction with fast protons, the (d,n) reaction with fast deuterons, or the like.
The radioisotopes are generated, mainly using fast proton beams or the like supplied from a cyclotron accelerator. In use of such a cyclotron, the system is large in scale and large-scale radiation shield equipment is needed, which poses a problem in terms of widespread use of the PET diagnoses. In contrast to it, if the cyclotron accelerator as a fast particle source is replaced with the aforementioned fast particle generating apparatus making use of the high-intensity laser beam, it will enable downsizing of the system including the radiation shield equipment.